Lighting device

Abstract

To provide a lighting device whose size is suppressed while preventing stray light and deterioration of optical efficiency.SOLUTION: The lighting device includes a light emitting element 1, a first lens 2 which receives light emitted from the light emitting element 1 and emits first emission light, and a second lens 3 which receives the first emission light and emits second emission light. Second lens 3 includes convex second incident surface 31 that receives the first emission light, convex second emission surface 32 that is provided on the right side in the drawing and emits the second emission light, and second side surface portion 33 formed between second incident surface 31 and second emission surface 32. Second side surface 33 includes first inclined surface 34 and second inclined surface 35 that are formed to be inclined with respect to the optical axis direction of light-emitting element 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lighting device having a cut-off function. [Background technology]

[0002] Conventionally, lighting devices such as vehicle headlights have been equipped with a cutoff function that cuts off the light emitted upward when used as low beam headlights to prevent oncoming vehicles and pedestrians from being dazzled. Also, floodlights used on outdoor grounds require a luminous intensity distribution that cuts off the light emitted upward to prevent light from leaking to the periphery of the ground.

[0003] Patent Document 1 discloses a vehicle headlamp that has a luminous intensity distribution that cuts off upper light when used as a passing headlamp. In Patent Document 1, the second reflecting surface formed on the first lens reflects light incident upward from the first lens downward, thereby cutting off the upper light.

[0004] Furthermore, the light reflected by the second reflecting surface is superimposed on the light not reflected by the second reflecting surface and is incident on the lower part of the second lens, thereby preventing a decrease in optical efficiency.

[0005] In addition, the second lens has a convex light entrance portion, which reduces the amount of light incident on the sidewalls (side surfaces) of the second lens and suppresses stray light that occurs when light that has entered the sidewalls of the second lens is reflected. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-206600 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in Patent Document 1, in order to reduce the light incident on the side wall of the second lens, the incident surface of the second lens needs to be larger than the exit surface of the first lens. For example, in order to block the light incident on the side wall of the second lens, the vertical length of the incident surface of the second lens needs to be approximately three times or more the vertical length of the exit surface of the first lens. This results in a large size of the lighting device.

[0008] An object of the present invention is to provide an illumination device that is small in size while preventing stray light and a decrease in optical efficiency. [Means for solving the problem]

[0009] In order to achieve the above object, an illumination device according to one embodiment of the present invention includes a light-emitting element, a first lens that receives light emitted from the light-emitting element and outputs a first output light, and a second lens that receives the first output light and outputs a second output light. The second lens includes a convex second input surface that receives the first output light, a convex second output surface that is located opposite the second input surface and outputs the second output light, and a second side surface portion formed between the second input surface and the second output surface. The second side surface portion is inclined with respect to a direction in which an optical axis of the light-emitting element extends. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce the size of the lighting device while preventing stray light and a decrease in optical efficiency. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a side view of the lighting device according to the embodiment. [Figure 2] FIG. 4 is a side view of a second lens according to the embodiment. [Figure 3] 10A to 10C are diagrams showing application examples of the lighting device according to the embodiment. [Figure 4] FIG. 10 is a side view of a second lens of a conventional lighting device. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0013] Fig. 1 shows a side view of the lighting device according to this embodiment, and Fig. 2 shows a side view of the second lens according to this embodiment. In the following description, the Z direction indicates the direction in which the optical axis of the light-emitting element extends (hereinafter also referred to as the optical axis direction of the light-emitting element 1), the Y direction indicates the up-down direction, and the X direction indicates the direction perpendicular to the Y and Z directions.

[0014] The lighting device according to this embodiment includes a light emitting element 1, a first lens 2, and a second lens 3.

[0015] The light emitting element 1 is composed of an LED or the like, and has an optical axis in the Z direction.

[0016] The first lens 2 receives light emitted from the light-emitting element 1 and emits a first emitted light to the second lens 3. Specifically, the first lens 2 has a first entrance 21, a first exit surface 22, and a first side surface portion 23 provided between the first entrance 21 and the first exit surface 22.

[0017] The first light entrance 21 is formed on the left side of the first lens 2 in the drawing, and is formed in a concave shape so as to surround the light emitting element 1. The first light entrance 21 receives the light emitted from the light emitting element 1.

[0018] The first side surface portion 23 includes a first reflecting surface 24 and a second reflecting surface 25.

[0019] First reflecting surface 24 is formed so as to spread diagonally upward to the right in the drawing and in the X direction from the upper end of the opening of first incident port 21. First reflecting surface 24 reflects light that has entered first lens 2 from first incident port 21 towards first exit surface 22 or second reflecting surface 25.

[0020] Second reflecting surface 25 is formed so as to extend diagonally downward to the left in the drawing and in the X direction from the lower end of first exit surface 22. Second reflecting surface 25 reflects light that has entered first lens 2 from first incident opening 21 toward first exit surface 22. Second reflecting surface 25 also reflects light reflected by first reflecting surface 24 toward first exit surface 22.

[0021] First emission surface 22 is formed on the right side of first lens 2 in the drawing. First emission surface 22 emits the light emitted from light-emitting element 1, the light reflected by first reflecting surface 24, and the light reflected by second reflecting surface 25 to second lens 3 as first emission light.

[0022] In the first lens 2, light emitted from the light-emitting element 1 toward the lower side of the drawing is reflected by the second reflecting surface 25 and emitted toward the upper side of the drawing from the first emitting surface 22. Therefore, the second reflecting surface 25 cuts off the light emitted from the first emitting surface 22 toward the lower side of the drawing.

[0023] Furthermore, light emitted from light-emitting element 1 toward the upper side of the drawing is reflected toward the lower side of the drawing by first reflecting surface 24 and toward the upper side of the drawing by second reflecting surface 25, and is therefore emitted toward the upper side of the drawing from first emitting surface 22. Therefore, first reflecting surface 24 and second reflecting surface 25 can increase the optical efficiency of the lighting device.

[0024] The second lens 3 receives the first output light emitted from the first lens 2 and outputs a second output light. The second lens 3 is an anamorphic lens with different curvatures in the Y and X directions. The thickness of the second lens 3 in the Y direction is greater than the thickness in the Z direction. Furthermore, the thickness of the second lens 3 in the Y direction is no more than twice the thickness of the first lens in the Y direction.

[0025] Specifically, the second lens 3 has a second entrance surface 31 , a second exit surface 32 , and a second side surface portion 33 provided between the second entrance surface 31 and the second exit surface 32 .

[0026] The second incident surface 31 is formed on the left side of the second lens 3 in the drawing, and is formed so as to be convex in the Z direction. The second incident surface 31 receives the first outgoing light emitted from the first exit surface 22 of the first lens 2.

[0027] Second exit surface 32 is formed on the right side of second lens 3 in the drawing, and is formed so as to be convex in the Z direction. Second exit surface 32 emits the light that has entered second lens 3 as second exit light.

[0028] Fig. 4 shows a side view of a conventional second lens. In the conventional second lens 3a, the lower part of the second side surface portion 33 in the drawing is formed by a flat surface 36 extending along the Z direction. In Fig. 4, emitted light R1 is light that is reflected by the first reflecting surface 24 of the first lens 2 and incident on the second incident surface 31. Furthermore, emitted light R2 is light that is reflected by the second reflecting surface 25 and incident on the second incident surface 31.

[0029] In the conventional second lens 3a, the emitted light R1 incident on the lower part of the second lens 3a in the drawing has a large angle of incidence with respect to the plane 36, and is therefore reflected by the plane 36 toward the upper part of the drawing. In addition, the emitted light R2 incident on the upper part of the second lens 3a in the drawing is partially reflected by the second emission surface 32 of the second lens 2. The emitted light R3 reflected by the second emission surface 32 is reflected by the plane 36 and the second entrance surface 31, and is emitted toward the upper part of the drawing. For this reason, in the conventional second lens 3a, the emitted light R1 and R3 each become stray light. To prevent this stray light, it was necessary to make the thickness of the second lens 2 in the Z direction sufficiently large.

[0030] Therefore, in the second lens according to this embodiment, a first inclined surface 34 and a second inclined surface 35 are formed at the lower part of the second side surface portion 33 in the drawing. The first inclined surface 34 and the second inclined surface 35 have their lower ends connected to each other.

[0031] The first inclined surface 34 is a flat surface formed to extend diagonally downward to the right in the drawing from the lower end of the second incident surface 31. The first inclined surface 34 is formed so that the angle θ1 it forms with the Z direction (the optical axis direction of the light-emitting element 1) is 20°.

[0032] The second inclined surface 35 is a flat surface formed to extend diagonally downward to the right in the drawing from the lower end of the second emission surface 32. The second inclined surface 35 is formed so that the angle θ2 it forms with the Z direction (the optical axis direction of the light-emitting element 1) is 20°.

[0033] 2, the angle θ2 between the second inclined surface 35 and the Z direction is 20°, so the angle of incidence of the output light R1 with respect to the second inclined surface 35 is small. Therefore, the output light R1 is not reflected by the second inclined surface 35 but is transmitted through it. As a result, the output light R1 is not output from the second output surface 32, so that the output light R1 can be easily blocked.

[0034] Furthermore, because the angle θ1 between the first inclined surface 34 and the Z direction is 20°, the angle of incidence of the output light R3 with respect to the first inclined surface 34 is small, and the output light R3 is transmitted through the first inclined surface 34 without being reflected by it. As a result, the output light R3 is not output from the second output surface 32, and therefore the output light R3 can be easily blocked.

[0035] With the above configuration, the second lens 3 includes a convex second incident surface 31 provided on the left side of the drawing and receiving the first emitted light, a convex second exit surface 32 provided on the right side of the drawing and emitting the second emitted light, and a second side surface 33 formed between the second incident surface 31 and the second exit surface 32. The second side surface 33 includes a first inclined surface 34 and a second inclined surface 35 formed to be inclined with respect to the Z direction (the optical axis direction of the light-emitting element 1). That is, because the second side surface 33 includes the first inclined surface 34 and the second inclined surface 35 inclined with respect to the Z direction, the emitted light beams R1 and R3 incident on the first inclined surface 34 and the second inclined surface 35 are less likely to be reflected and are more likely to be transmitted through the first inclined surface 34 and the second inclined surface 35. As a result, the emitted light beams R1 and R3 are less likely to be emitted from the second exit surface 32, and the emitted light beams R1 and R3 can be easily blocked while reducing the size of the lighting device. Therefore, it is possible to prevent stray light and a decrease in optical efficiency while keeping the size small.

[0036] Moreover, the first inclined surface 34 and the second inclined surface 35 are flat surfaces. This prevents the surface shape of the second lens 3 from becoming complex, making the second lens 3 easier to manufacture.

[0037] Furthermore, the angle between the extending direction of the flat surface of each of the first inclined surface 34 and the second inclined surface 35 and the Z direction is 20°. As a result, the outgoing light R1 reflected by the first reflecting surface 24 and incident on the second side surface portion 33 passes through the second inclined surface 35, and the outgoing light R3 reflected by the second outgoing surface 32 and incident on the second side surface portion 33 passes through the first inclined surface 34, so that the outgoing light R1 and R3 can be easily blocked. Furthermore, since the angles formed by the first inclined surface 34 and the second inclined surface 35 and the Z direction are small, the size of the lighting device can be reduced.

[0038] FIG. 3 is a diagram showing an illumination device according to this embodiment in which first lenses and second lenses are arranged in an array. As shown in FIG. 3, a plurality of first lenses 2 and a plurality of second lenses 3 are arranged at equal intervals in the Y direction. The plurality of first lenses 2 and the plurality of second lenses 3 are fixed by fixing portions 41 and 42 extending in the Y direction, respectively. According to this embodiment, the thickness of the second lens 3 in the Y direction can be made thinner than that of the conventional second lens 3a shown in FIG. 4. This makes it possible to reduce the size of the illumination device when the first lenses 2 and second lenses 3 are arranged in an array, as shown in FIG. 3.

[0039] (Other embodiments) As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

[0040] In the above embodiment, the angles θ1 and θ2 formed by the first inclined surface 34 and the second inclined surface 35 of the second lens 3 with respect to the Z direction are not limited to 20°. For example, the angles θ1 and θ2 may each be 30° or less. This allows the size of the lighting device to be reduced.

[0041] In the above embodiment, the second side surface portion 33 of the second lens 3 may include a flat surface other than the first inclined surface 34 and the second inclined surface 35. The second side surface portion 33 of the second lens 3 may include a curved surface without including either the first inclined surface 34 or the second inclined surface 35. However, the second side surface portion 33 of the second lens 3 may include a surface that is inclined with respect to the Z direction. [Industrial Applicability]

[0042] The lighting device of the present invention can be applied to lighting devices having a cut-off function, such as vehicle headlights and floodlights installed on the ground. [Explanation of symbols]

[0043] 1 Light-emitting element 2 First lens 3 Second lens 21 1st entrance part 22 First exit surface 23 First side part 24 1st reflective surface 25 Second reflective surface 31 2nd entrance plane 32 Second exit surface 33 Second side part 34 1st slope 35 Second slope

Claims

1. A light-emitting element; a first lens that receives light emitted from the light emitting element and emits first emitted light; a second lens that receives the first emitted light and emits a second emitted light; Equipped with The second lens is a convex second incident surface that receives the first emitted light; a convex second exit surface that is provided at a position opposite to the second entrance surface and that emits the second exit light; a second side surface portion formed between the second incident surface and the second exit surface; Equipped with The second side surface portion includes a surface inclined with respect to the optical axis direction of the light-emitting element. A lighting device characterized by:

2. 2. The lighting device according to claim 1, 11. A lighting device according to claim 10, wherein the inclined surface of the second side surface portion is formed by a plurality of flat surfaces.

3. 3. The lighting device according to claim 2, The plurality of planes are: a first inclined surface formed so as to extend from an end of the second incident surface toward the second exit surface; a second inclined surface extending from an end of the second light exit surface toward the second light entrance surface and formed to be connected to the first inclined surface, The lighting device is characterized in that the first inclined surface and the second inclined surface are each formed so that the angle formed with the optical axis direction of the light-emitting element is 30° or less.

4. The lighting device according to any one of claims 1 to 3, The first lens is a first light incident opening formed in a concave shape to cover the light emitting element and to receive light generated by the light emitting element; a first exit surface formed at a position opposite to the first entrance and through which the first exit light is emitted; a first side surface portion formed between the first entrance and the first exit surface; Equipped with The first side surface portion is a first reflecting surface that reflects light incident on the first light entrance from the light emitting element toward the first light exit surface; a second reflecting surface that reflects the light incident on the first entrance from the light emitting element and the light reflected by the first reflecting surface toward the first exit surface; A lighting device characterized by:

5. The lighting device according to any one of claims 1 to 4, The illumination device, wherein the second light exit surface has a vertical length that is equal to or less than twice the vertical length of the first light exit surface.

6. The lighting device according to any one of claims 1 to 5, An illumination device, characterized in that a combination of the first lens and the second lens is arranged in an array.

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